Solid state light sheet and bare die semiconductor circuits with series connected bare die circuit elements

ABSTRACT

An electronically active sheet includes a bottom substrate having a bottom electrically conductive surface. A top substrate having a top electrically conductive surface is disposed facing the bottom electrically conductive surface. An electrical insulator separates the bottom electrically conductive surface from the top electrically conductive surface. At least one bare die electronic element is provided having a top conductive side and a bottom conductive side. Each bare die electronic element is disposed so that the top conductive side is in electrical communication with the top electrically conductive surface and so that the bottom conductive side is in electrical communication with the bottom electrically conductive surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.11/454,479 filed Jun. 16, 2006.

BACKGROUND OF THE INVENTION

The present invention pertains to a semiconductor roll-to-roll and batchmanufacturing methods. The present invention also pertains to a lightemitting diode light sheet and methods for manufacturing the same. Moreparticularly, the present invention pertains to an inorganic lightemitting diode light sheet that can be used as a photo-radiation sourcefor applications including, but not limited to, general illumination,architectural lighting, novelty lighting, display backlighting, heads-updisplays, commercial and roadway signage, monochromatic and full-colorstatic and video displays, a radiation-source for photo-curablematerials, patterned light emissive images, scrolling displays, friendor foe identification, and the like. Further, the present inventionpertains more particularly to an inorganic light active sheet that canbe used as a light-to-energy device for converting photo-radiation toelectrical energy for applications including, but not limited to, solarpanels, CCD-type cameras, photo-sensors, and the like. Further, thepresent invention pertains more particularly, to methods formass-producing the inventive light active sheet at relatively low cost.

Inorganic light emitting diodes (LED) are based on elements of theperiodic table of a vast variety. They come out of semiconductortechnology, and indeed, a semiconductor diode such as a silicon diode,or a germanium diode were among the first semiconductor devices. Thesewere made by doping the silicon or the germanium with a small amount ofimpurity to make n-type (excess electrons) or p-type (excess holes) inthe material. LEDs emit light because of the materials selected so thatthe light is emitted in the ultra-violet, visible, or infrared ranges ofthe spectrum. The types of materials used are made from vapor depositionof materials on semiconductor wafers and cut into dice (a single one isa die). Typically, the die, or LED dice, are about 12 mil sq. Thecomposition of the dice depends on the color, for example some red diceare AlInGaAs and some blue dice are InGaN. The variations are typically“three-five” variations, so-called because they vary based on the thirdand fifth period of the periodic table to provide the n- and p-typematerials.

The conversion of an LED die into an LED lamp is a costly process,involving very precise handling and placement of the tiny LED die. TheLED dice are most simply prepared as 3 mm LED lamps. The die isrobotically placed in a split cup with electrodes on each side. Theentire structure is encased in a plastic lens that attempts to focus thebeam more narrowly. High brightness dice may also be surface mountedwith current-driving and voltage limiting circuits, and elaborate heatsink and heat removal schemes. Connection is by soldering or solderlessultrasonic wire bond methods. The result is a discrete point source oflight. The LED lamp has a pair of leads, which can then be soldered to aprinted circuit board. The cost of forming the lamp and then solderingthe lamp to a printed circuit board is a relatively expensive process.Accordingly, there is a need to reduce the cost of forming a lightemitting device based on the LED die.

As an example application of LED lamps, it has recently been shown thatultraviolet LED lamps can be used to cure photo-polymerizable organicmaterials (see, for example, Loctite® 7700 Hand Held LED Light Source,Henkel-Loctite Corporation, Rocky Hill, Conn.).

Photo-polymerizable organic materials are well known and are used forapplications such as adhesives, binders and product manufacturing.Photo-polymerization occurs in monomer and polymer materials by thecross-linking of polymeric material. Typically, these materials arepolymerized using radiation emitted from sources of light includingintensity flood systems, high intensity wands, chambers, conveyors andunshielded light sources.

As an example use of photo-polymerizable organic materials, precisionoptical bonding and mounting of glass, plastics and fiber optics can beobtained with photo-polymerizable adhesives. These materials can be usedfor opto-mechanical assembly, fiber optic bonding and splicing, lensbonding and the attachment of ceramic, glass, quartz, metal and plasticcomponents.

Among the drawbacks of the conventional systems that utilizephoto-polymerizable organic materials is the requirement of a highintensity photo-radiation source. Typically, light sources, such asmercury vapor lamps, have been used to generate the radiation needed forphoto-polymerization. However, these light sources are an inefficientradiation source because most of the energy put in to drive the lamp iswasted as heat. This heat must be removed from the system, increasingthe overall bulk and cost. Also, the lamps have relatively short servicelife-times, typically around 1000 hours, and are very costly to replace.The light that is output from these light sources usually covers a muchbroader spectrum than the photo-radiation wavelengths that are neededfor photo-polymerization. Much of the light output is wasted. Also,although the material can be formulated to be hardened at otherwavelengths, the typical photo-polymerizable organic material ishardened at one of the peak output wavelengths of the mercury vaporlamp, to increase the polymerization efficiency. This peak outputwavelength is in the UV region of the radiation spectrum. This UVradiation is harmful to humans, and additional shielding and protectiveprecautions such as UV-filtering goggles are needed to protect theoperators of such equipment.

FIG. 66 is a side view of an inorganic LED die available. A conventionalinorganic LED die is available from many manufacturers, typically has arelatively narrow radiation emission spectrum, is relatively energyefficient, has a long service life and is solid-state and durable. Thedie shown is an example of an AlGaAs/AlGaAs red die, obtained fromTyntek Corporation, Taiwan. These dice have dimensions roughly 12 mil×12mil×8 mil, making them very small point light sources. As shown in FIG.67, in a conventional LED lamp, this die is held in a metal cup so thatone electrode of the die (e.g., the anode) is in contact with the baseof the cup. The metal cup is part of an anode lead. The other electrodeof the die (e.g., the cathode) has a very thin wire soldered or wirebonded to it, with the other end of the wire soldered or wire bonded toan anode lead. The cup, die, wire and portions of the anode and cathodeleads are encased in a plastic lens with the anode and cathode leadsprotruding from the lens base. These leads are typically solder or wirebonded to a circuit board to selectively provide power to the die andcause it to emit light. It is very difficult to manufacture theseconventional lamps due to the very small size of the die, and the needto solder or wire bond such a small wire to such a small die electrode.Further, the plastic lens material is a poor heat conductor and the cupprovides little heat sink capacity. As the die heats up its efficiencyis reduced, limiting the service conditions, power efficiency and lightoutput potential of the lamp. The bulkiness of the plastic lens materialand the need to solder or wire bond the lamp leads to an electricalpower source limits emissive source packing density and the potentialoutput intensity per surface area.

There is a need for a photo-radiation source that is energy efficient,generates less heat, is low cost and that has a narrow, broad and/orvariable spectrum of radiation emission wavelength and intensity. Atypical LED consists of a sub-millimeter sized die of light emittingmaterial that is electrically connected to an anode lead and a cathodelead. The die is encased within a plastic lens material. However, theprocessing that takes the LED dice and turns it into an LED lamp istedious and sophisticated, mostly due to the very small size of the LEDdie. It is very difficult to solder or wire bond directly to the dice,and so it is common practice to use LED lamps that are then solder orwire bonded onto a circuit board. Conventionally, LED lamps have beensolder or wire bonded onto a circuit board in a formation to create asource of photo-radiation for photo-polymerizable organic materials.

This solution is far from optimum, since the relatively high cost of theLED lamps keeps the overall cost of the photo-radiation source high.There is a need for a photo-radiation source that can use the LED dicedirectly, without the need for the lamp construction or a direct solderor wire bonded connection between the anode and cathode of the die. Suchas system would have an efficient die packing density, enabling ahigh-intensity photo-radiation source having a narrow emission band.

Wantanabe et al., published patent application US2004/0195576A1, teachesa device and method for forming a transparent electrode over thelight-emitting portion of an LED die. This reference is concerned withovercoming the difficulty of forming an electrode accurately at thelight output surface of a minute LED device (10 square microns). Aconventional LED is 300 square microns. The reference states thatforming a transparent electrode on a semiconductor device so as not toshield emitted light is already known. The crux of the Wantanabeinvention is to form a transparent electrode directly and specificallyover the light output face of a tiny LED device, or an array of suchdevices, instead of the conventional bonding or soldering of an opaquewire to connect the LED device to a power supply line or lead. To formthe transparent electrode on such a small device, this reference teachesthe use of semiconductor and/or printed circuit board techniques.

An example of the steps of forming the Wantanabe device consist of:

1) Providing a substrate

2) Forming p-side wiring on the substrate

3) Transferring a light emitting diode onto the substrate so the p sideof the diode is connected to the wiring

4) Forming an insulation resin layer to cover the substrate, wiring anddiode

5) Selectively removing the insulation resin to expose the n-sidesurfaces of the diode

6) Forming n-side wiring on the surface of the insulation resin

7) Forming a transparent electrode connecting the n-side of the diode tothe n-side wiring

The steps for forming the transparent electrode are:

7a) Forming a resist film to cover the insulation resin and the exposedn-side surfaces

7b) Selectively removing the resist layer to form an opening portiondefining the light output surface of the diode and the n-side wiring

7c) Applying an electrode paste to the opening portion and the resistfilm

7d) Removing the electrode paste from the resist film to leave electrodepaste only where the opening portion is so that the light output surfaceof the diode and the n-side wiring are connected.

There are variations disclosed to the various steps and materials used,but in essence, the same cumbersome PCB-type processes are described ineach of the examples. This reference shows that it is known to form atransparent electrode using PCB techniques on the light output surfaceof a diode to reduce the shielding of light emitted from the diode. But,replacing the conventionally-used opaque wire with a transparentelectrode film is not new and is in the public domain (see, Lawrence etal, U.S. Pat. No. 4,495,514).

Oberman, U.S. Pat. No. 5,925,897, teaches using a diode powder betweenconductive contacts, forming a conductor/emissive layer/conductor devicestructure. The diode powder consists of crystal particles 10-100 micronsin size. The diode powder is formed by heating a mixture of In and Ga ina crucible and flowing nitrogen gas over the heated mixture. This powdernow contains all n-type material. The powder is adhered to a glass platethat is coated with an appropriate contact metal. A p-type dopant isdiffused into the powder crystals to form a p-region and the p-n diodejunction. A top substrate with a transparent conductive surface isplaced on the powder and the entire structure thermally annealed toenhance the adhesion of the powder to the upper contact. Oberman statesthat the conventional LED is typically fabricated by connectingelectrical contacts to the p and n regions of individual dies, andenclosing the entire LED die in a plastic package. Oberman's diodepowder is specifically based on an observation that surfaces, interfacesand dislocations appear to not adversely affect the light emittingproperties of III-V nitrides. This reference says that thestate-of-the-art nitride LED is grown on a sapphire substrate, and sincesapphire is non-conducting, both electrical contacts are made from thetop of the structure.

Wickenden et al., U.S. Pat. No. 4,335,501, teaches a method formanufacturing a monolithic LED array. The individual LEDs are formed bycutting isolation channels through a slice of n-type material. Thechannels are cut in two steps, a first step is cutting a gap into theback of the slice of n-type material and then this gap is filled withglass. Then, in a second step the front of the slice is cut to completethe channel and the front cut is also filled with glass. Once theisolation channels have been formed, the tops of the remaining blocks ofn-type material are doped to become p-type and the n-p junction of eachLED formed. Beam leads are formed connecting the p-regions of the LEDs.

Nath, et al., WO92/06144 and U.S. Pat. No. 5,273,608, teaches a methodfor laminating thin film photovoltaic devices with a protective sheet.The method provides the encapsulation of thin-film devices such asflexible solar cells within a top insulating substrate and a bottominsulating substrate. Nath's description of the relevant prior art showsthat encapsulating thin film devices between insulating sheets is notnew. This reference teaches that the use of a heated roller isundesirable. Nath's invention is to a specific method that heats a wholeroll of composite material all at once to avoid the use of heatedrollers. Nath teaches a new method for protecting and encapsulating thinfilm devices. Encapsulating thin film devices between insulating sheetsis not new, but Nath teaches a specific method that avoids the use ofheated rollers.

SUMMARY OF THE INVENTION

The present invention is intended to overcome the drawbacks of the priorart. It is an object of the present invention to provide methods formanufacturing solid-state light active devices. It is another object ofthe present invention to provide device structures for solid-state lightactive devices. It is yet another object of the present invention toprovide a method of making a light sheet material. It is yet anotherobject of the present invention to provide a method of manufacturing anencapsulated semiconductor circuit using a roll-to-roll fabricationprocess. It is yet another object of the present invention to provide aflat panel (eg LCD) display back light. It is yet another object of thepresent invention to provide a solid state general illumination source.It is yet another object of the present invention to provide a thin,flexible, durable, addressable display. It is yet another object of thepresent invention to provide a thin, flexible, durable, solid state baredie electronic circuit.

An electronically active sheet includes a bottom substrate having abottom electrically conductive surface. A top substrate having a topelectrically conductive surface is disposed facing the bottomelectrically conductive surface. An electrical insulator separates thebottom electrically conductive surface from the top electricallyconductive surface. At least one bare die electronic element is providedhaving a top conductive side and a bottom conductive side. Each bare dieelectronic element is disposed so that the top conductive side is inelectrical communication with the top electrically conductive surfaceand so that the bottom conductive side is in electrical communicationwith the bottom electrically conductive surface.

The electrical insulator may comprise a hotmelt adhesive. Each bare dieelectronic element is embedded in the hot melt electrical insulator withthe top conductive side and the bottom conductive side left uncovered bythe electrical insulator. The electrical insulator binds the topsubstrate to the bottom substrate with the top conductive side of thebare die electronic element in electrical communication with the topelectrically conductive pattern of the top substrate, and so that thebottom conductive side of the bare die electronic element is inelectrical communication with the bottom conductive pattern of thebottom substrate. At least one electronic element may comprise a solidstate semiconductor light emitting diode bare die.

The bare die electronic element can include a first conductor and asecond conductor both disposed on either the top conductive side and thebottom conductive side, and wherein said bare die electronic element isdisposed so that the first conductor and the second conductor are inelectrical communication with respective wiring lines formed on eitherthe top substrate and the bottom substrate.

The bare die electronic element may be plurality of individual bare dieLED elements. The bottom electrically conductive surface and the topelectrically conductive surface are formed as a respective x and ywiring grid for selectively addressing the individual bare die LEDelements for forming a display.

A phosphor or other re-emitter can be provided in or on at least one ofthe top substrate and the bottom substrate (or adjacent thereto), orformed in the electrical insulator. The phosphor or other re-emitter isoptically stimulated by a radiation emission of a first wavelength fromthe light active semiconductor element to emit light of a secondwavelength. Alternatively, the phosphor can be disposed between the topand bottom conductive surfaces and electrically stimulated to emitlight. In this construction electronic circuit elements, such as LEDbare die, can be incorporated into a light sheet integrally formed withan electroluminescent (EL) phosphor light element.

In accordance with the present invention, a bare die semiconductorelectronic circuit is provided comprising a first substrate having abottom side surface having at least a first and a second conductiveline. A second substrate is disposed adjacent to the first substrate.The second substrate has a top side surface having a third conductiveline. A least one bare die semiconductor electronic circuit elementhaving a first electrode and a second electrode disposed on an obverseside and a third electrode disposed on a reverse side is provided. Anadhesive adheres the first substrate to the second substrate and bindsthe bare die semiconductor electronic circuit element to the firstsubstrate and to the second substrate. The adhesive maintains the firstelectrode in electrical communication with the first conductive line,the second electrode in electrical communication with the secondconductive line, and the third electrode is in electrical communicationwith the third conductive line. At least one of the first and the secondsubstrate may be a flexible plastic sheet, such as PET, PEN, Kapton,polycarbonate, vinyl, and the like. At least one of the first, secondand third wiring line can formed from a printed conductive ink, such asthrough silk screen, inkjet, gravure, donor sheet, electrostatic orother printing methods. Alternatively, the conductive lines can beformed by etching. The adhesive may be at least one of a hot melt andthermosetting adhesive. Alternatively, the adhesive may be at least oneof a thermally active adhesive, a catalyst active adhesive, a solventevaporation active adhesive and a radiation active adhesive.

In accordance with the present invention, a first substrate is providedhaving bottom side surface having at least a first and a secondconductive line. A bare die semiconductor electronic circuit element isprovided having a first electrode and a second electrode disposed on anobverse side. An adhesive encapsulates and adheres the bare diesemiconductor electronic circuit element to the first substrate so thatthe first electrode is in electrical communication with the firstconductive line and the second electrode is in electrical communicationwith the second conductive line. A second substrate can be disposedadjacent to the first substrate and bound to the first substrate by theadhesive.

The second substrate can include a top side surface having a thirdconductive line. The bare die semiconductor electronic circuit elementincludes a third electrode disposed on its reverse side. The adhesiveencapsulates and adheres the bare die semiconductor electronic circuitelement to the second substrate so that said third electrode is inelectrical communication with the third conductive line.

An electrically conductive through-hole can be disposed in either thefirst substrate and/or the second substrate for electrically connectingthe bare die semiconductor electronic circuit element to a conductiveelement disposed on a top side surface of the first substrate and/or ona bottom side surface of the second substrate.

A second bare die semiconductor electronic circuit element can beprovided having at least one electrode. The adhesive encapsulates andadheres the second bare die semiconductor electronic circuit element tothe first substrate so that the electrode of the second bare diesemiconductor electronic circuit element is in electrical communicationwith at least one of the first electrode and the second electrodethrough the respective first and second conductive line.

In accordance with another aspect of the invention, an ultra-thinelectronically active sheet is provided. At least one bare dieelectronic element is embedded in an electrical insulator. The bare dieelectronic element has at least a first conductive feature and a secondconductive feature left uncovered by the electrical insulator. A firstconductive structure disposed on the electrical insulator iselectrically connected to the first conductive feature. A secondconductive structure disposed on the electrical insulator andelectrically connected with the second conductive feature.

An active and passive radiation emitting device for identifyingpersonnel, locations or goods includes a first substrate having a firstconductive surface. A pattern of active radiation emitting semiconductorelements are in electrical communication with the conductive surface sothat when the conductive surface is energized the radiation emittingsemiconductor elements emit radiation of at least a first wavelength. Asecond substrate is provided and an adhesive encapsulates and adheresthe bare radiation emitting semiconductor elements to the firstsubstrate and securing the second substrate to the first substrate. Atleast one of a passive radiation reflecting surface and an activethermal radiation source are fixed to at least one the first substrateand the second substrate. The passive radiation reflecting surfacereflects radiation from an external radiation source and the activethermal radiation source provides a detectable thermal or far IRemission.

A light emitting device includes a first bottom substrate having anelectrically conductive surface. A second bottom substrate having anelectrically conductive surface is provided adjacent to but electricallyisolated from the first bottom substrate. A first bare die lightemitting diode device having a top p junction conductor and a bottom njunction conductor is provided in electrical communication with theelectrically conductive surface of the first bottom conductor. A secondbare die light emitting diode device having a top n junction conductorand a bottom p junction conductor is provided in electricalcommunication with the electrically conductive surface of the secondbottom conductor. The p/n junctions of the diodes may be reversed. A topsubstrate has a conductive surface in electrical communication with boththe top n junction conductor of the first bare die light emitting diodedevice and the top p junction conductor of the second bare die lightemitting diode device. The electrically conductive surface of the topsubstrate is effective for putting the first bare die light emittingdiode device and the second bare die light emitting diode device into aseries electrical connection.

The electrically conductive surface can be provided with a predeterminedresistance value effective to create the equivalent of a ballastresistor within a desired resistance range in series with the first baredie light emitting diode device and the second bare die light emittingdiode device. This equivalent ballast resistor enables the bare dielight emitting diode devices to be driven at a desired current level fora given voltage applied to the first and the second bottom substrates.The equivalent ballast resistor can be adjusted, through the selectionof materials or geometry, so that the first and the second bare dielight emitting diode devices can be connected in series even if they donot have the same electrical characteristics.

Subsequent bottom substrates and top substrates can be provided so thatmultiple series devices are connected. Depending on the chosenmaterials, geometry and LED bare die chips, an AC driven variableintensity, variable color 110V (or 220V) source lighting device can beprovided. Other voltages and wavelength emissions are also possibleusing this inventive construction.

A light emitting device, comprising a first bottom substrate having anelectrically conductive surface. A second bottom substrate is providedhaving an electrically conductive surface. A first bare die lightemitting diode device having a top p junction conductor and a bottom njunction conductor is provided. The bottom n junction conductor is inelectrical communication with the electrically conductive surface of thefirst bottom conductor. A second bare die light emitting diode device isprovided having a top n junction conductor and a bottom p junctionconductor. The bottom p junction conductor is in electricalcommunication with the electrically conductive surface of the secondbottom conductor. A top substrate having a conductive surface isprovided with the conductive surface in electrical communication withboth the top p junction conductor of the first bare die light emittingdiode device and the top n junction conductor of the second bare dielight emitting diode device. The electrically conductive surface of thetop substrate completes an electrical circuit with the first bare dielight emitting diode device and the second bare die light emitting diodedevice in a series electrical connection. When a voltage of the correctpolarity is applied to the first and the second bottom substrates, thelight emitting diodes light up. When a voltage of opposite polarity isapplied to the first and second bottom substrates, the series connectedlight emitting diode block electron flow. Other circuit elements canalso be connected in parallel or series with the bare die light emittingdiodes.

The electrically conductive surface of at least the first bottomsubstrate, the second bottom substrate and the top substrate has apredetermined resistance value effective to create a ballast resistor inseries with the first bare die light emitting diode device and thesecond bare die light emitting diode device. In accordance with thisaspect of the present invention, conventionally required discreteresistors are not needed. By selecting the proper materials, it is thuspossible to create a light emitting device that can be connected to apredetermined voltage source, such as a 12 volt system of an automobile,truck or boat.

At least one subsequent bottom substrate can be provided havingsubsequent electrically conductive surface. Subsequent bare die lightemitting diodes can be provided with opposite polarities in electricalcommunication with the subsequent electrically conductive surface. Atleast one subsequent top substrate having a subsequent top conductivesurface in electrical communication with the subsequent bare die lightemitting diodes is provided so that the subsequent bare die lightemitting diodes are connected in series.

Opposite polarity bare die light emitting diode devices can beelectrically connected in respective opposite polarity to and along withthe first bare die light emitting diode device and the second bare dielight emitting diode device to form a light emitting device that emitslight when driven with an AC voltage.

An adhesive adheres the top substrate to the first bottom substrate andto the second bottom substrate. The adhesive also encapsulating thefirst bare die light emitting diode device and the second bare die lightemitting diode device. The adhesive adheres the first bare die lightemitting diode device to the first bottom substrate and to the topsubstrate while maintaining the electrical communication between the topp junction conductor of the first bare die light emitting diode deviceto the conductive surface of the first bottom substrate. The adhesivealso maintains the electrical communication between the bottom njunction conductor of the first bare die light emitting diode device tothe conductive surface of the top substrate. The adhesive adheres thesecond bare die light emitting diode device to the second bottomsubstrate and to the top substrate while maintaining the electricalcommunication between the bottom p junction conductor of the second baredie light emitting diode device to the conductive surface of the secondbottom substrate. The adhesive also maintaining the electricalcommunication between the top n junction conductor of the second baredie light emitting diode device to the conductive surface of the topsubstrate. The adhesive may comprise at least one of a thermally activeadhesive, a catalyst active adhesive, a solvent evaporation activeadhesive and a radiation active adhesive.

The first and the second bare die light emitting diode devices areembedded in the adhesive with respective top conductive side and thebottom conductive side left at least partially uncovered by theadhesive. This allows the adhesive to bind the first bottom substrateand the second bottom substrate to the top substrate with the first andthe second bare die light emitting diode devices in electricalcommunication with the respective conductive surfaces.

A bare die semiconductor circuit includes a first substrate having anelectrically conductive surface. A second substrate is provided havingan electrically conductive surface. A first bare die semiconductorcircuit element has a first conductor and a second conductor. The secondconductor of the first bare die semiconductor circuit element is inelectrical communication with the electrically conductive surface of thefirst substrate. A second bare die semiconductor circuit element has afirst conductor and a second conductor. The second conductor of thesecond bare die semiconductor circuit element is in electricalcommunication with the electrically conductive surface of the secondsubstrate. A series connecting substrate has a conductive surface. Theconductive surface of the series connecting substrate is in electricalcommunication with both the first conductor of the first bare diesemiconductor circuit element and the first conductor of the second baredie semiconductor circuit element. The electrically conductive surfaceof the series connecting substrate is effective for putting the firstbare die semiconductor circuit element and the second bare diesemiconductor circuit element into a series electrical connection.

The present invention pertains to a solid state light emitting devicehaving series connected bare die light emitting diode devices forforming a higher voltage light emitting device. A first substrate isprovided having an electrically conductive surface. A second substratealso has an electrically conductive surface. A first bare die lightemitting diode device is provided having a first junction of a firstpolarity and a second junction of a second polarity. The second junctionof the first bare die light emitting diode device is in electricalcommunication with the electrically conductive surface of the firstsubstrate. A second bare die light emitting diode device is providedhaving a first junction of the second polarity and a second junction ofthe first polarity. The second junction of the second bare die lightemitting diode device is in electrical communication with theelectrically conductive surface of the second substrate. A seriesconnecting substrate is provided having a conductive surface. Theconductive surface of the series connecting substrate is in electricalcommunication with both the first junction of the first bare die lightemitting diode device and the first junction of the second bare dielight emitting diode device. The electrically conductive surface of theseries connecting substrate being effective for putting the first baredie light emitting diode device and the second bare die light emittingdiode device into a series electrical connection.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file contains at least one drawing executed incolor. Copies of this patent or patent application publication withcolor drawings will be provided by the Office upon request and paymentof the necessary fee.

FIG. 1 is a graph illustrating an AC driving voltage applied to red andblue LED devices having opposite polarity in accordance with anembodiment of the inventive RGGB variable color light sheet;

FIG. 2 is a graph illustrating an AC driving voltage applied to greenLED devices in accordance with an embodiment of the inventive RGGBvariable color light sheet;

FIG. 3 shows a comb electrode pattern having printed silver inkelectrodes and printed transparent conductor pads;

FIG. 4 illustrates the driving of two RGGB pixel elements in accordancewith the embodiment of the inventive RGGB variable color light sheet;

FIG. 5 illustrate driving the inventive RGGB variable color light sheetas a lower resolution variable color intensity back light for an LCDdisplay;

FIG. 6 shows an example of the higher resolution LCD image that is backlit by the variable color intensity back light show in FIG. 5;

FIG. 7 is a back substrate silver ink pattern for a thin, flexiblepixilated display tile;

FIG. 8 is a front substrate silver ink pattern for the thin, flexiblepixilated display tile;

FIG. 9 is a front substrate transparent conductor (e.g., printed A-ITO)pattern for the thin, flexible pixilated display tile;

FIG. 10 is a front substrate insulation pattern for the thin, flexiblepixilated display tile, the insulation pattern being provided to reducecross-talk;

FIG. 11 is a front substrate printed signage pattern for the thin,flexible pixilated display tile;

FIG. 12 illustrates the cross-section of the back (bottom) substratesilver ink pattern for a thin, flexible pixilated display tile;

FIG. 13 illustrates the cross-section of the front substrate silver inkpattern for the thin, flexible pixilated display tile;

FIG. 14 illustrates the cross-section of the front substrate transparentconductor (e.g., printed A-ITO) pattern formed on the front substratesilver ink pattern for the thin, flexible pixilated display tile;

FIG. 15 illustrates the cross-section of the front substrate insulationpattern formed on the silver ink and transparent conductor patterns forthe thin, flexible pixilated display tile, the insulation pattern beingprovided to reduce cross-talk;

FIG. 16 illustrates the cross-section of the inventive thin, flexiblepixilated display tile with a printed signage graphic;

FIG. 17 illustrates a first printed conductive line formed under aninsulating layer formed under a second crossing printed conductive linein accordance with an embodiment of the inventive electronic bare diecircuit;

FIG. 18 illustrates an assembled x (bottom substrate) and y (topsubstrate) conductive pattern for a bare die LED backlight for anotebook computer;

FIG. 19 illustrates the x (bottom substrate) conductive pattern for tbare die LED backlight for a notebook computer;

FIG. 20 illustrates the y (top substrate) conductive pattern for a baredie LED backlight for a notebook computer;

FIG. 21 is a cross section unassembled view showing a top conductivesurface on a top release sheet, a melt adhesive with embedded bare diesmiddle layer, and a bottom conductive surface on a bottom release sheetin accordance with an ultra-thin LED light sheet;

FIG. 22 is a cross section assembled after lamination view showing thetop conductive surface on a top release sheet, the melt adhesive withembedded bare dies middle layer, and the bottom conductive surface on abottom release sheet in accordance with the ultra-thin LED light sheet;

FIG. 23 is a cross section assembled view showing the peeling off of thetop release sheet from the top conductive surface and the bottom releasesheet from the bottom conductive surface in accordance with theultra-thin LED light sheet;

FIG. 24 is a cross section showing the resulting ultra-thin LED lightsheet;

FIG. 25 shows a conductive pattern of an embodiment of the inventivelight sheet that does not require a transparent conductive window forletting light emit from a top emitting LED die;

FIG. 26 is a close up view of a conductively patterned window forelectrically connecting the conductive pattern to the top electrode of atop emitting LED die;

FIG. 26 is a cross section showing a top emitting LED die electricallyconnected to the conductively patterned window of the embodiment of theinventive light sheet that does not require a transparent conductivewindow;

FIG. 27 illustrates individual RGBY light strips for an embodiment ofthe variable color and intensity light sheet;

FIG. 28 shows the light strips assembled for an RGBYG variable color andintensity light sheet;

FIG. 29 shows an alternative assembled RGBG variable color and intensitylight sheet;

FIG. 30 illustrates the pattern of the alternative assembled RGBGvariable color and intensity light sheet shown in FIG. 29;

FIG. 31 illustrates the G (green emitting LED die) pattern;

FIG. 32 illustrates the B (blue emitting LED die) pattern;

FIG. 33 illustrates the R (red emitting LED die) pattern;

FIG. 34 shows the cross sections of the individual color strips of RGBGlight strips showing the differences in bare die height;

FIG. 35 illustrates the use of different adhesive thicknesses toaccommodate the difference in bare die height;

FIG. 36 illustrates the use of a thickness increasing material toaccommodate the difference in bare die height;

FIG. 37 illustrates a method of placing LED bare dies or electroniccircuit semiconductor elements directly from a wafer tape into a meltadhesive;

FIG. 38 shows the construction of a light tape that can be cut tolength;

FIG. 39 is an exploded cross sectional view showing a bare dietransistor element connected with a connection enhancing material to athin, flexible, encapsulated electronic circuit in accordance with thepresent invention;

FIG. 40 is an assembled cross sectional view showing the bare dietransistor element connected with the connection enhancing material tothe thin, flexible, encapsulated electronic circuit;

FIG. 41 is an exploded cross sectional view showing a bare dietransistor element connected directly to wiring lines of a thin,flexible, encapsulated electronic circuit in accordance with the presentinvention;

FIG. 42 is an assembled cross sectional view showing the bare dietransistor element connected directly to wiring lines of the thin,flexible, encapsulated electronic circuit;

FIG. 43 is a schematic view illustrating a roll laminator formanufacturing an encapsulated electronic bare die circuit in accordancewith the present invention;

FIG. 44 is a top down view of a conventional LED bare die showing ametal bonding pad electrode formed on the top emitting face of theconventional LED bare die where it blocks the emission of light;

FIG. 45 is a top down view of an inventive LED bare die showing a topemissive face without a metal bonding pad electrode enabling unblockedemission of light;

FIG. 46 is a cross section of a light sheet having an inventive LED baredie as shown in FIG. 45 including electron injection facilitatingmaterial for connecting to the bare LED emissive face;

FIG. 47 is a cross sectional view of a light sheet having a side emitterLED bare die connected to a conductive line formed on a transparentsubstrate;

FIG. 48 is a cross section of a light sheet having a conventional LEDbare die as shown in FIG. 44 including electron injection facilitatingmaterial for connecting to the metal bonding pad electrode formed on theLED emissive face;

FIG. 49 is a cross sectional view of an inventive self-contained batteryand solar cell integrally formed with the inventive light sheet;

FIG. 50 is a cross section of an ultra-thin construction of theinventive light sheet;

FIG. 51 illustrates a light sheet construction for making multipledevices cut from a single light sheet;

FIG. 52 shows a light strip cut from the single light sheet shown inFIG. 52 showing a crimp-on terminal connector;

FIG. 53 shows a multiple-strip light strip cut from the single lightsheet shown in FIG. 52;

FIG. 54 shows an inventive method of forming an electrical connection tobare die electrodes of a flip-chip style bare die semiconductor device;

FIG. 55 shows an electronic circuit formed using the inventive bare dieelectronic circuit manufacturing method for connecting a bare diecapacitor, a bare die transistor and a bare die LED;

FIG. 56 shows an electronic circuit similar to FIG. 55 with a heightcompensating wiring line formed on a substrate for compensating adifference in heights of a horizontal electrode structure LED bare die;

FIG. 57( a) is a cross sectional view of a higher voltage light sheetutilizing opposite polarity LED bare die for forming a series connectionresulting in a higher device voltage;

FIG. 57( b) is a top view of the higher voltage light sheet shown inFIG. 57( a) and cut from a multiple module light sheet constructed alongthe lines shown in FIGS. 58 through 60;

FIG. 58 shows multiple higher voltage light sheet devices formed as asingle light sheet (or in a roll-to-roll process) and constructed sothat each higher voltage device is connected in series with the otherhigher voltage devices on the sheet or roll resulting in successivelyhigher operating voltages depending on the numbers of series connecteddevices;

FIG. 59 is a top view of assembled elements of a light sheet constructedin accordance with the higher voltage light sheet construction shown inFIGS. 57 and 58;

FIG. 60 is a top view of top transparent substrate strips for completingthe light sheet construction shown in FIG. 59;

FIG. 61 is a cross sectional view of an alternative construction of ahigher voltage light sheet;

FIG. 62 is a top view of a top substrate for the alternativeconstruction of a higher voltage light sheet shown in FIG. 61;

FIG. 63 is a top view of a bottom substrate for the alternativeconstruction of a higher voltage light sheet shown in FIG. 61;

FIG. 64 shows an exploded view of an inventive construction of the lightsheet utilizing a coin cell battery with LED bare die having appropriatepolarity fixed directly to the positive and negative sides of thebattery;

FIG. 65 shows an assembled view of the inventive construction of thelight sheet shown in FIG. 64;

FIG. 66 is an alternate construction of the light sheet showing only themetal substrates connected to a coin cell battery;

FIG. 67 shows a camouflaged housing for the inventive light sheetmimicking the color, size and texture of a rock;

FIG. 68 shows an exploded view of an alternate construction of the lightsheet showing a hot melt spacer for forming a battery pouch between thetop and bottom substrates;

FIG. 69 is a cross sectional assembled view of the light sheetconstruction shown in FIG. 68;

FIG. 70 is a top view of an alternative construction of the light sheet;

FIG. 71 is an exploded view of a coin battery light sheet constructionon a metal substrate;

FIG. 72 is a cross sectional view of the alternative construction shownin FIG. 71;

FIG. 73 is an assembled view of the coin battery light sheetconstruction shown in FIG. 71;

FIG. 74 is a view of the coin battery light sheet construction shown inFIG. 71 after forming;

FIG. 75 is an assembled and formed view of the inventive coin batterylight sheet construction shown in FIG. 71;

FIG. 76 is a cross sectional view of a multiple radiation emitter lightsheet for emitting radiation of different wavelengths;

FIG. 77 is an exploded view of a light sheet construction havingpatterned LED bare die and patterned thermal energy emitters;

FIG. 78 is a cross sectional view of a light sheet construction having aconductive line for connecting with a side emitting LED bare die;

FIG. 79 is a side view and block diagram showing a construction of thelight sheet including a first wavelength emitter and a second wavelengthemitter, at least the second wavelength emitter being driven by a pulsegenerator, and a remotely located detector for detecting at least one ofthe first and second emitted wavelengths, as well as for detecting apulse;

FIG. 80 is a photograph showing a higher voltage device being driven atabout 50 volts AC and constructed along the lines of the light sheetconstructions shown in FIGS. 57 to 63, two series connected devicesbeing capable of connecting directly to a conventional 110VAC wall plug;

FIG. 81 is a photograph showing a higher voltage device cut from thedevice shown in FIG. 80 and constructed to be driven at 12 volts DC whenconnected in either polarity (top device) compared with a conventionallyconstructed printed circuit board having conventionally packaged LEDlamp, resistors, and rectifying diodes soldered to a conventional PCB(bottom device);

FIG. 82 is a photograph showing a notebook computer keyboard lightconstructed along the lines of FIGS. 18 to 20;

FIG. 83 is a photograph showing the notebook computer keyboard lightshown in FIG. 82 lighting up a notebook computer keyboard;

FIG. 84 shows a thin, lightweight, flexible pixilated scrolling messagedisplay constructed along the lines of FIG. 3;

FIG. 85 is a photograph showing a large format, thin, lightweight,flexible display having assembled display tiles making up individualdisplay pixels;

FIG. 86 is a photograph of a coin battery light sheet constructed alongthe lines shown in FIGS. 71 through 75 before being formed and showingthe forming die;

FIG. 87 is a photograph of the coin battery light sheet shown in FIG. 86after being formed and with a coin battery inserted;

FIG. 88 shows a light sheet being used to light up a cup holder;

FIG. 89 shows a light sheet having multiple light sheet stripsconstructed along the lines shown in FIGS. 51-53 for being used as afishing lure;

FIG. 90 shows a thin, flexible light sheet constructed on a half-hardcopper back substrate and having a size of about 8 inches square; and

FIG. 91 shows an infrared light sheet for providing identificationthrough the emission of a wavelength that is invisible to human vision.

DETAILED DESCRIPTION OF THE INVENTION

For purposes of promoting an understanding of the principles of theinvention, reference will now be made to the embodiments illustrated inthe drawings and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of theinvention is thereby intended, there being contemplated such alterationsand modifications of the illustrated device, and such furtherapplications of the principles of the invention as disclosed herein, aswould normally occur to one skilled in the art to which the inventionpertains.

FIG. 1 is a graph illustrating an AC driving voltage applied to red andblue LED devices having opposite polarity in accordance with anembodiment of the inventive RGGB variable color light sheet. FIG. 2 is agraph illustrating an AC driving voltage applied to green LED devices inaccordance with an embodiment of the inventive RGGB variable color lightsheet. FIG. 3 shows a comb electrode pattern having printed silver inkelectrodes and printed transparent conductor pads. FIG. 4 illustratesthe driving of two RGGB pixel elements in accordance with the embodimentof the inventive RGGB variable color light sheet.

FIGS. 1-4 shows a single layer RGB light sheet constructed so that therelative intensities of each color LED bare die can be controlled. Thisconstruction allows a light sheet to produce any color visible lightincluding white. The bare dies are selected so that Blue and Red areopposite polarity. Blue and Red are on the same comb electrode pattern(i.e., blue bare die and red bare die on the same ITO pad). Green is onthe other comb electrode pattern. The electrodes are driven with ACvoltage, both comb electrodes may be in phase but driven with variablevoltages. The amplitude of each leg of the blue/red AC driving voltageis adjustable to separately control the intensity of the blue and redemitting LEDs. The amplitude of the driving leg of the green AC drivingvoltage is adjustable to separately control the intensity of the greenemitting LEDs. The electrode pattern can be an x and y grid enablingaddressable RGB elements

FIG. 5 illustrate driving the inventive RGGB variable color light sheetas a lower resolution variable color intensity back light for an LCDdisplay. FIG. 6 shows an example of the higher resolution LCD image thatis back lit by the variable color intensity back light show in FIG. 5.FIG. 5-6 show an inventive display backlight. A conventional backlightgenerates a uniform color, eg, white light, for backlighting a pixilatedimage display, such as an LCD filter. In accordance with the presentinvention, the backlight may be controlled to provide a lower resolutioncolor source that matches the color of the image that is to be displayedthrough the LCD filter. In this example, the backlight area that isilluminating the yellow sun is controlled so that the appropriatebacklight LED elements produce a relatively higher intensity yellowlight. While, the backlight area that is illuminating the sky iscontrolled so that the appropriate backlight LED elements produce arelatively higher intensity blue light. The backlight is controlled inresponse to the image information (eg, a television signal) that isapplied for controlling the higher resolution LCD filter array. By thuscontrolling the backlight, a more energy efficient, higher fidelity,improved image is displayed using, for example, an LCD video display.

FIG. 7 is a back substrate silver ink pattern for a thin, flexiblepixilated display tile. FIG. 8 is a front substrate silver ink patternfor the thin, flexible pixilated display tile. FIG. 9 is a frontsubstrate transparent conductor (e.g., printed A-ITO) pattern for thethin, flexible pixilated display tile. FIG. 10 is a front substrateinsulation pattern for the thin, flexible pixilated display tile, theinsulation pattern being provided to reduce cross-talk. FIG. 11 is afront substrate printed signage pattern for the thin, flexible pixilateddisplay tile. FIG. 12 illustrates the cross-section of the back (bottom)substrate silver ink pattern for a thin, flexible pixilated displaytile. FIG. 13 illustrates the cross-section of the front substratesilver ink pattern for the thin, flexible pixilated display tile. FIG.14 illustrates the cross-section of the front substrate transparentconductor (e.g., printed A-ITO) pattern formed on the front substratesilver ink pattern for the thin, flexible pixilated display tile. FIG.15 illustrates the cross-section of the front substrate insulationpattern formed on the silver ink and transparent conductor patterns forthe thin, flexible pixilated display tile, the insulation pattern beingprovided to reduce cross-talk. FIG. 16 illustrates the cross-section ofthe inventive thin, flexible pixilated display tile with a printedsignage graphic.

FIG. 17 illustrates a first printed conductive line formed under aninsulating layer formed under a second crossing printed conductive linein accordance with an embodiment of the inventive electronic bare diecircuit. FIG. 17 shows insulation material printed in a pattern thatallows wiring lines to cross over without connection (insulation inbetween conductive lines), and to cross over with connection (noinsulation between conductive lines). This feature enables complexelectronic bare die and/or packaged die circuits.

FIG. 18 illustrates an assembled x (bottom substrate) and y (topsubstrate) conductive pattern for a bare die LED backlight for anotebook computer. FIG. 19 illustrates the x (bottom substrate)conductive pattern for t bare die LED backlight for a notebook computer.FIG. 20 illustrates the y (top substrate) conductive pattern for a baredie LED backlight for a notebook computer. FIG. 18-20 shows aconstruction of the inventive light sheet that enables the keys of anelectronic device keyboard to be individually lit up using somethinglike a passive matrix driving circuit. An addressable keyboard lightallows additional functionality to be provided for conveying informationor entertaining a user. For example, keyboard shortcuts can be lit upand controlled by different software applications. E.g., the active keysfor a software game can be lit. The keys can be controlled in responsemusic being played through the computer speakers, etc. Variable colorscan be obtained by providing two or more bare dies of driven to producea desired color pattern. Additional buss lines, windows and pads can beprovided to create a full-color RGB light. This version enables the keysor groups of keys to be lit up with any selected color.

FIG. 21 is a cross section unassembled view showing a top conductivesurface on a top release sheet, a melt adhesive with embedded bare diesmiddle layer, and a bottom conductive surface on a bottom release sheetin accordance with an ultra-thin LED light sheet. FIG. 22 is a crosssection assembled after lamination view showing the top conductivesurface on a top release sheet, the melt adhesive with embedded baredies middle layer, and the bottom conductive surface on a bottom releasesheet in accordance with the ultra-thin LED light sheet. FIG. 23 is across section assembled view showing the peeling off of the top releasesheet from the top conductive surface and the bottom release sheet fromthe bottom conductive surface in accordance with the ultra-thin LEDlight sheet. FIG. 24 is a cross section showing the resulting ultra-thinLED light sheet.

In accordance with this aspect of the invention, an ultra-thinelectronically active sheet is provided. At least one bare dieelectronic element is embedded in an electrical insulator. The bare dieelectronic element has at least a first conductive feature and a secondconductive feature left uncovered by the electrical insulator. A firstconductive structure disposed on the electrical insulator iselectrically connected to the first conductive feature. A secondconductive structure disposed on the electrical insulator andelectrically connected with the second conductive feature. Thisultra-thin light sheet can be used, for example, for keyboardbacklighting for mobile phones, PDAs and other devices where thinnessand/or flexibility are particularly important.

FIG. 25 shows a conductive pattern of an embodiment of the inventivelight sheet that does not require a transparent conductive window forletting light emit from a top emitting LED die. FIG. 26 is a close upview of a conductively patterned window for electrically connecting theconductive pattern to the top electrode of a top emitting LED die. FIGS.25-26 shows a light sheet construction that does not require atransparent conductor. A transmissive window is provided with thinconductive lines connected with thicker buss lines. The LED die isconnected to the thin lines and light emitted from the LED istransmitted through the transmissive window. Alternatively, thetransmissive window may be slightly smaller (at least in one dimension)than the edges of the bare die so that the bare die makes contact withthe thicker buss lines. The conductive pattern enables light from baredie to emit through clear windows while the bare die is electricallyconnected with the patterned conductive lines.

FIG. 27 illustrates individual RGBY light strips for an embodiment ofthe variable color and intensity light sheet. FIG. 28 shows the lightstrips assembled for an RGBYG variable color and intensity light sheet.FIG. 29 shows an alternative assembled RGBG variable color and intensitylight sheet. FIG. 30 illustrates the pattern of the alternativeassembled RGBG variable color and intensity light sheet shown in FIG.29. FIG. 31 illustrates the G (green emitting LED die) pattern. FIG. 32illustrates the B (blue emitting LED die) pattern. FIG. 33 illustratesthe R (red emitting LED die) pattern;

FIGS. 27-33 show a white light (e.g. display backlight) formed byseparate light strips for each color. This construction enables finetuning of the materials and processes for each particular bare die type.

FIG. 34 shows the cross sections of the individual color strips of RGBGlight strips showing the differences in bare die height. FIG. 35illustrates the use of different adhesive thicknesses to accommodate thedifference in bare die height. FIG. 36 illustrates the use of athickness increasing material to accommodate the difference in bare dieheight. For example, bare die heights vary depending on color, foundryand recipe. Bare die LEDs can have a vertical (top bottom) or horizontal(top top) electrode pattern. The inventive construction enables thecorrect thickness and formula adhesive, conductive lines, and substratesused to optimize the light output for each bare die type used toconstruct the inventive

FIG. 37 illustrates a method of placing LED bare dies or electroniccircuit semiconductor elements directly from a wafer tape into a meltadhesive. FIG. 38 shows the construction of a light tape that can be cutto length. FIGS. 37-38 show a light strip made by providing electricalcontact with the conductive surface of the top substrate, so that aconnection can be made through the buss to the conductive surface and tothe LED die. The buss and the conductive bottom substrate provide aconductive pathway to each LED such that the light strip can be cutanywhere along its length. An electrical connection to the buss and theconductive bottom substrate of each cut strip energizes the LEDs andgenerates light.

FIG. 39 is an exploded cross sectional view showing a bare dietransistor element connected with a connection enhancing material to athin, flexible, encapsulated electronic circuit in accordance with thepresent invention.

FIG. 40 is an assembled cross sectional view showing the bare dietransistor element connected with the connection enhancing material tothe thin, flexible, encapsulated electronic circuit.

FIG. 41 is an exploded cross sectional view showing a bare dietransistor element connected directly to wiring lines of a thin,flexible, encapsulated electronic circuit in accordance with the presentinvention. FIG. 42 is an assembled cross sectional view showing the baredie transistor element connected directly to wiring lines of the thin,flexible, encapsulated electronic circuit. FIGS. 41-42 show a connectionenhancing material which can be a conductive adhesive, such as a z-axisconductor, or a low temperature alloy that softens or melts during thelamination process or during a connection-making heat and pressureprocess. A printable ink may be used that includes low melt conductiveparticles in a binder. Additional conductivity enhancing materials canbe included in the ink as well. The connection enhancing materialprovides a mechanical and electrical connection to the electrodes of thebare die device. In a connection step, the connection enhancing elements(e.g., round balls) are compressed and may be deformed intointerconnecting elements (e.g., platelets) to secure a good electricalconnection between the electrodes of the bare die device and the wiringlines.

In accordance with the present invention, a bare die semiconductorelectronic circuit is provided comprising a first substrate having abottom side surface having at least a first and a second conductiveline. A second substrate is disposed adjacent to the first substrate.The second substrate has a top side surface having a third conductiveline. A least one bare die semiconductor electronic circuit elementhaving a first electrode and a second electrode disposed on an obverseside and a third electrode disposed on a reverse side is provided. Asshown in FIG. 42, a bare die transistor circuit element is connecteddirectly to wiring lines or lands printed on flexible substrates. Anadhesive adheres the first substrate to the second substrate and bindsthe bare die semiconductor electronic circuit element to the firstsubstrate and to the second substrate. The adhesive maintains the firstelectrode in electrical communication with the first conductive line,the second electrode in electrical communication with the secondconductive line, and the third electrode is in electrical communicationwith the third conductive line. At least one of the first and the secondsubstrate may be a flexible plastic sheet, such as PET, PEN, Kapton,polycarbonate, vinyl, and the like. At least one of the first, secondand third wiring line can formed from a printed conductive ink, such asthrough silk screen, inkjet, gravure, donor sheet, electrostatic orother printing methods. Alternatively, the conductive lines can beformed by etching. The adhesive may be at least one of a hot melt andthermosetting adhesive. Alternatively, the adhesive may be at least oneof a thermally active adhesive, a catalyst active adhesive, a solventevaporation active adhesive and a radiation active adhesive.

FIG. 43 is a schematic view illustrating a roll laminator formanufacturing an encapsulated electronic bare die circuit in accordancewith the present invention. FIG. 43 shows a laminator for manufacturingthe inventive light sheet. A pre-heating zone raises the thermal energyof the lamination sandwich. The heat shoes heat the conveyor belts andthe heated rollers (which may be separately heated). The conveyor beltsmaintain positive pressure on the lamination package as it cools. Thecooling rollers may be provided to add pressure and speed cooling of thelamination to lock in the electrical connections between theelectrically conductive element as the hot melt adhesive cools. Fans andchill rollers may be provided to further take heat from the laminationpackage.

FIG. 44 is a top down view of a conventional LED bare die showing ametal bonding pad electrode formed on the top emitting face of theconventional LED bare die where it blocks the emission of light. FIG. 45is a top down view of an inventive LED bare die showing a top emissiveface without a metal bonding pad electrode enabling unblocked emissionof light. FIG. 46 is a cross section of a light sheet having aninventive LED bare die as shown in FIG. 45 including electron injectionfacilitating material for connecting to the bare LED emissive face. FIG.47 is a cross sectional view of a light sheet having a side emitter LEDbare die connected to a conductive line formed on a transparentsubstrate. FIG. 48 is a cross section of a light sheet having aconventional LED bare die as shown in FIG. 44 including electroninjection facilitating material for connecting to the metal bonding padelectrode formed on the LED emissive face.

In accordance with this aspect of the invention, an electronicallyactive sheet includes a bottom substrate having a bottom electricallyconductive surface. A top substrate having a top electrically conductivesurface is disposed facing the bottom electrically conductive surface.An electrical insulator separates the bottom electrically conductivesurface from the top electrically conductive surface. At least one baredie electronic element is provided having a top conductive side and abottom conductive side. Each bare die electronic element is disposed sothat the top conductive side is in electrical communication with the topelectrically conductive surface and so that the bottom conductive sideis in electrical communication with the bottom electrically conductivesurface.

The electrical insulator may comprise a hotmelt adhesive. Each bare dieelectronic element is embedded in the hot melt electrical insulator withthe top conductive side and the bottom conductive side left uncovered bythe electrical insulator. The electrical insulator binds the topsubstrate to the bottom substrate with the top conductive side of thebare die electronic element in electrical communication with the topelectrically conductive pattern of the top substrate, and so that thebottom conductive side of the bare die electronic element is inelectrical communication with the bottom conductive pattern of thebottom substrate. At least one electronic element may comprise a solidstate semiconductor light emitting diode bare die.

As shown, for example, in FIGS. 39 through 42, the bare die electronicelement can include a first conductor and a second conductor bothdisposed on either the top conductive side and the bottom conductiveside, and wherein said bare die electronic element is disposed so thatthe first conductor and the second conductor are in electricalcommunication with respective wiring lines formed on either the topsubstrate and the bottom substrate.

As shown, for example, in FIG. 7 through 16, the top and bottomconductive patterns formed on the top and bottom substrates can beprinted, etched, or otherwise electrically isolated and patterned toform electrode grids. The bare die electronic element may be pluralityof individual bare die LED elements. The bottom electrically conductivesurface and the top electrically conductive surface can thus be formedas a respective x and y wiring grid for selectively addressing theindividual bare die LED elements for forming a display.

A phosphor or other re-emitter can be provided in or on at least one ofthe top substrate and the bottom substrate (or adjacent thereto), orformed in the electrical insulator. The phosphor or other re-emitter isoptically stimulated by a radiation emission of a first wavelength fromthe light active semiconductor element to emit light of a secondwavelength. Alternatively, the phosphor can be disposed between the topand bottom conductive surfaces and electrically stimulated to emitlight. In this construction electronic circuit elements, such as LEDbare die, can be incorporated into a light sheet integrally formed withan electroluminescent (EL) phosphor light element.

FIG. 49 is a cross sectional view of an inventive self-contained batteryand solar cell integrally formed with the inventive light sheet. FIG. 49shows a light sheet construction wherein a battery cathode may be, forexample, film of lithium metal. The battery anode material can be acarbon material component of a conventional Li battery. A solar cell,patterned to allow light to escape, can be provided to charge thebattery. A light sensitive switch can be provided so that the LEDs turnon at a certain ambient darkness. Elements of the light sensitive switchcircuit can be provided as bare die connected within the light sheet.The result is a very thin, flexible, self-charging, automatic turn-onlight sheet system. The system may be used, for example, as an IRemissive sheet for military use, to mark streets with visible lightpatterns, to provide decorative or architectural lighting, etc.

FIG. 50 is a cross section of an ultra-thin construction of theinventive light sheet. FIG. 50 shows an ultra-thin light sheet. Arelease substrate is coated with a top conductor and a bottom conductor.When release sheet is removed, the adhesive holds the device componentstogether resulting in ultra-thin light sheet. Applications includemobile phone keypads, backlights, etc.

FIG. 51 illustrates a light sheet construction for making multipledevices cut from a single light sheet. FIG. 52 shows a light strip cutfrom the single light sheet shown in FIG. 52 showing a crimp-on terminalconnector. FIG. 53 shows a multiple-strip light strip cut from thesingle light sheet shown in FIG. 52. FIG. 51-53 shows hole punches andknife slices through substrate(s) can be used to create control linepatterns before and/or after the lamination process. The hole punchesand knife slices are used to cut wiring lines to provide desired circuitconstructions.

FIG. 54 shows an inventive method of forming an electrical connection tobare die electrodes of a flip-chip style bare die semiconductor device.A flip-chip style die is placed directly onto a hot melt adhesive layerformed on a substrate. A top substrate is provided having electrode landpatterns corresponding to the electrodes of the flip-chip style die.Other circuit elements and conductive lines can be included (not shown).The top substrate is registered (through alignment pins (not shown)etc.) to the bottom substrate so that the chip electrodes and therespective electrode lands come into to face-to-face electrical contact.The thus-formed lamination sandwich is laminated through a roll or presslamination process so that the flip-chip style die are pressed into andencapsulated by the hot melt adhesive. The flip-chip style die arecompletely encapsulated by the top and bottom substrate, and the hotmelt adhesive. The hot melt adhesive also securely fixes the twosubstrates together forming a durable, flexible, protected electroniccircuit.

FIG. 55 shows an electronic circuit formed using the inventive bare dieelectronic circuit manufacturing method for connecting a bare diecapacitor, a bare die transistor and a bare die LED. FIG. 56 shows anelectronic circuit similar to FIG. 55 with a height compensating wiringline formed on a substrate for compensating a difference in heights of ahorizontal electrode structure LED bare die. FIGS. 55-56 show a bare diepixel matrix. When a signal is applied to capacitor, the transistorpasses current through the LED bare die for the duration of thecapacitor discharge. Other elements and other constructions arepossible, using bare die or hybrid of bare die and conventional packagedelectronic elements. The height compensating wiring line enables unevenelectrodes to be connected. The height compensating wiring lines canalso be used to allow chips of different heights to be provided on thesame device.

In accordance with this aspect of the invention, a first substrate isprovided having bottom side surface having at least a first and a secondconductive line. A bare die semiconductor electronic circuit element isprovided having a first electrode and a second electrode disposed on anobverse side. An adhesive encapsulates and adheres the bare diesemiconductor electronic circuit element to the first substrate so thatthe first electrode is in electrical communication with the firstconductive line and the second electrode is in electrical communicationwith the second conductive line. A second substrate can be disposedadjacent to the first substrate and bound to the first substrate by theadhesive.

The second substrate can include a top side surface having a thirdconductive line. The bare die semiconductor electronic circuit elementincludes a third electrode disposed on its reverse side. The adhesiveencapsulates and adheres the bare die semiconductor electronic circuitelement to the second substrate so that said third electrode is inelectrical communication with the third conductive line.

An electrically conductive through-hole can be disposed in either thefirst substrate and/or the second substrate for electrically connectingthe bare die semiconductor electronic circuit element to a conductiveelement disposed on a top side surface of the first substrate and/or ona bottom side surface of the second substrate.

A second bare die semiconductor electronic circuit element can beprovided having at least one electrode. The adhesive encapsulates andadheres the second bare die semiconductor electronic circuit element tothe first substrate so that the electrode of the second bare diesemiconductor electronic circuit element is in electrical communicationwith at least one of the first electrode and the second electrodethrough the respective first and second conductive line.

FIG. 57( a) is a cross sectional view of a higher voltage light sheetutilizing opposite polarity LED bare die for forming a series connectionresulting in a higher device voltage. As shown, copper strips or slugsare provided as conductive bottom substrates and heat sinks. The copperstrips may be fixed together by a pressure sensitive adhesive andsupported on a supports substrate, such as PET, forming a bottomcomposite substrate. A hot melt adhesive layer is adhered to the bottomcomposite substrate. LED die of a first polarity are encapsulated in theadhesive on a first copper strip and LED die of a second polarity areencapsulated in the adhesive on a second copper strip. The bottomconductor of the LED die are in electrical communication with therespective first and second copper strips. A conductive top substrate isprovided in electrical contact with the top conductors of both LED die.A lens may be provided on top of or integrally formed with the topsubstrate to enhance the beam pattern produced by the LED die. Since theLED die are of opposite polarity, a completed circuit is formed when avoltage of a first polarity if applied to the first copper strip and avoltage of a second polarity is applied to the second copper strip. Theresistance value of the conductive top substrate can be selected toprovide an in-series ballast resistor so that the voltage applied at thecopper strips can be tailored for specific applications, such as a 12volt automobile power source.

This construction can be used to create a light sheet that can beplugged directly into a household current. The resistance values can beminimized to create a high efficiency solid state lighting system thatcan be driven with a constant current power supply. This construction isadaptable to a roll-to-roll or sheet fabrication process, with daughtermodules of desired driving voltage being cut from a mother board-typesheet or roll. This construction can be used for source lighting,display back lighting, transportation signal, interior and exteriorlighting and many other applications.

FIG. 57( b) is a top view of the higher voltage light sheet shown inFIG. 57( a) and cut from a multiple module light sheet constructed alongthe lines shown in FIGS. 58 through 60. A light emitting device includesa first bottom substrate having an electrically conductive surface. Asecond bottom substrate having an electrically conductive surface isprovided adjacent to but electrically isolated from the first bottomsubstrate. A first bare die light emitting diode device having a top pjunction conductor and a bottom n junction conductor is provided inelectrical communication with the electrically conductive surface of thefirst bottom conductor. A second bare die light emitting diode devicehaving a top n junction conductor and a bottom p junction conductor isprovided in electrical communication with the electrically conductivesurface of the second bottom conductor. The p/n junctions of the diodesmay be reversed. A top substrate has a conductive surface in electricalcommunication with both the top p junction conductor of the first baredie light emitting diode device and the top n junction conductor of thesecond bare die light emitting diode device. The electrically conductivesurface of the top substrate is effective for putting the first bare dielight emitting diode device and the second bare die light emitting diodedevice into a series electrical connection.

The electrically conductive surface can be provided with a predeterminedresistance value effective to create the equivalent of a ballastresistor within a desired resistance range in series with the first baredie light emitting diode device and the second bare die light emittingdiode device. This equivalent ballast resistor enables the bare dielight emitting diode devices to be driven at a desired current level fora given voltage applied to the first and the second bottom substrates.The equivalent ballast resistor can be adjusted, through the selectionof materials or geometry, so that the first and the second bare dielight emitting diode devices can be connected in series even if they donot have the same electrical characteristics.

Subsequent bottom substrates and top substrates can be provided so thatmultiple series devices are connected. Depending on the chosenmaterials, geometry and LED bare die chips, an AC driven variableintensity, variable color 110V (or 220V) source lighting device can beprovided. Other voltages and wavelength emissions are also possibleusing this inventive construction.

To form higher voltage devices, a third bare die light emitting diodedevice having a top p junction conductor and a bottom n junctionconductor is provided. The bottom n junction conductor is in electricalcommunication with the electrically conductive surface of the secondbottom conductor. At least one subsequent bottom substrate is providedwith a subsequent electrically conductive surface. Subsequent bare dielight emitting diodes are provided in electrical communication with thesubsequent electrically conductive surface. At least one subsequent topsubstrate having a subsequent top conductive surface in electricalcommunication with the third bare die light emitting diode and thesubsequent bare die light emitting diodes so that the subsequent baredie light emitting diodes are connected in series. To make highervoltage devices, and/or for forming daughter modules that can be cutfrom a mother sheet, additional subsequent series connection substratesas needed are provided having a subsequent series connecting conductivesurface in electrical communication with remaining subsequent bare dielight emitting diode devices so that the subsequent bare die lightemitting diodes on the at least one subsequent substrates are connectedin series.

That is, to form higher voltage device, at least one subsequent bottomsubstrates having subsequent electrically conductive surfaces. Bare dielight emitting diodes with opposite polarity are provided in electricalcommunication with the subsequent electrically conductive surfaces. Atleast one subsequent top substrate having a subsequent top conductivesurface is in electrical communication with the subsequent bare dielight emitting diodes so that the subsequent bare die light emittingdiodes are connected in series. Thus, as more elements are added inseries, the driving voltage of the light sheet increase. In accordancewith the present invention, the light sheet can be constructed so thatit emits light when connected with either polarity DC voltage. Theopposite polarity bare die light emitting diode devices are inelectrically connected with the electrically conductive surface and thetop substrate and electrically conductive surface of the first andsecond bottom substrates. The opposite polarity bare die light emittingdiode devices are electrically connected in respective opposite polarityto and along with the first bare die light emitting diode device and thesecond bare die light emitting diode device. This construction alsoenables the device to be driven so that it will emit light when drivenwith an AC voltage. The LED die are of opposite polarity within eachseries connected portion of the light sheet circuit, and connected suchthat they will be emitting light or blocking electron flow depending onthe polarity of the AC voltage leg.

FIG. 58 shows multiple higher voltage light sheet devices formed as asingle light sheet (or in a roll-to-roll process) and constructed sothat each higher voltage device is connected in series with the otherhigher voltage devices on the sheet or roll resulting in successivelyhigher operating voltages depending on the numbers of series connecteddevices. FIG. 59 is a top view of assembled elements of a light sheetconstructed in accordance with the higher voltage light sheetconstruction shown in FIGS. 57 and 58. FIG. 60 is a top view of toptransparent substrate strips for completing the light sheet constructionshown in FIG. 59. By building up successive in-series devices, higherand higher source voltages can be accommodated. Also, by placing chipsof opposite polarity on each copper strip, an AC circuit can be created.This construction also provides through holes that can be used duringthe manufacturing process for alignment of the components as well as toprovide solder, crimp or clamp connection points directly on the copperstrips. Thus, the more difficult electrical terminal connection to thethin flexible plastic substrate is avoided.

FIG. 61 is a cross sectional view of an alternative construction of ahigher voltage light sheet. FIG. 62 is a top view of a top substrate forthe alternative construction of a higher voltage light sheet shown inFIG. 61. FIG. 63 is a top view of a bottom substrate for the alternativeconstruction of a higher voltage light sheet shown in FIG. 61.

FIG. 64 shows an exploded view of an inventive construction of the lightsheet utilizing a coin cell battery with LED bare die having appropriatepolarity fixed directly to the positive and negative sides of thebattery. FIG. 65 shows an assembled view of the inventive constructionof the light sheet shown in FIG. 64. FIG. 66 is an alternateconstruction of the light sheet showing only the metal substratesconnected to a coin cell battery. In this case, a light sheet can beconnected to the metal substrates or the metal substrates can beprovided as at least one of the light sheet substrates. FIG. 67 shows acamouflaged housing for the inventive light sheet mimicking the color,size and texture of a rock.

FIG. 68 shows an exploded view of an alternate construction of the lightsheet showing a hot melt spacer for forming a battery pouch between thetop and bottom substrates. FIG. 69 is a cross sectional assembled viewof the light sheet construction shown in FIG. 68. FIG. 70 is a top viewof an alternative construction of the light sheet. This constructionenables a very low cost device to be manufactured without theconventionally required etched and drilled printed circuit board,soldered packaged LED lamps, diodes and resistors, battery connectionschemes, etc.

FIG. 71 is an exploded view of a coin battery light sheet constructionon a metal substrate. FIG. 72 is a cross sectional view of thealternative construction shown in FIG. 71. FIG. 73 is an assembled viewof the coin battery light sheet construction shown in FIG. 71. FIG. 74is a view of the coin battery light sheet construction shown in FIG. 71after forming. FIG. 75 is an assembled and formed view of the inventivecoin battery light sheet construction shown in FIG. 71. Thisconstruction enables a completed light emitting device to be formed veryinexpensively from just bare LED die, substrates, conductive tape, inkor foil, and adhesive. Because the device is formed with a metalsubstrate, it can be die-formed into a shape that accommodates andsecurely connects a coin battery. The result is a small, inexpensivelight emitting device with a replaceable battery.

FIG. 76 is a cross sectional view of a multiple radiation emitter lightsheet for emitting radiation of different wavelengths. FIG. 77 is anexploded view of a light sheet construction having patterned LED baredie and patterned thermal energy emitters. The multiple wavelengthsemitted can be in the visible and invisible ranges. Also, a passivereflector can be provided to that the device can act as a passive andactive signal emitter. The radiation emitters can be patterned foridentification and to improve the radiation emissive quality.

FIG. 78 is a cross sectional view of a light sheet construction having aconductive line for connecting with a side emitting LED bare die. Sideemitting LED bare die are available the emit the majority of their lightthrough the sides rather than through the top face of the die. Theseemitters can be used to provide a more uniform light from the lightsheet when desired by reducing the hot spots of the bare die emitter.The adhesive and substrates can be selected to closely match the indexof refraction of the LED die to further enhance light output. Also,additives can be provided within the adhesive to assist in lightdiffusion, wavelength conversion (e.g., phosphors for white light fromblue or UV emission), selective blocking and light channeling, etc.

FIG. 79 is a side view and block diagram showing a construction of thelight sheet including a first wavelength emitter and a second wavelengthemitter, at least the second wavelength emitter being driven by a pulsegenerator, and a remotely located detector for detecting at least one ofthe first and second emitted wavelengths, as well as for detecting apulse. For example, the first wavelength can be near-ir radiation andthe second wavelength can be farther into the IR spectrum and pulsed todistinguish the wavelength emission from a warm body.

In accordance with this aspect of the invention, an active and passiveradiation emitting device for identifying personnel, locations or goodsincludes a first substrate having a first conductive surface. A patternof active radiation emitting semiconductor elements are in electricalcommunication with the conductive surface so that when the conductivesurface is energized the radiation emitting semiconductor elements emitradiation of at least a first wavelength. A second substrate is providedand an adhesive encapsulates and adheres the bare radiation emittingsemiconductor elements to the first substrate and securing the secondsubstrate to the first substrate. At least one of a passive radiationreflecting surface and an active thermal radiation source are fixed toat least one the first substrate and the second substrate. The passiveradiation reflecting surface reflects radiation from an externalradiation source and the active thermal radiation source provides adetectable thermal or far IR emission.

FIG. 80 is a photograph showing a higher voltage device being driven atabout 50 volts AC and constructed along the lines of the light sheetconstructions shown in FIGS. 57 to 63. Two series connected devicesbeing capable of connecting directly to a conventional 110VAC wall plug.Alternative constructions of this device include a maximum efficiencydevice where there is little or no ballast resistor associated with theLED bare die (such as the side emitter construction shown in FIG. 78and/or the transparent window construction shown in FIGS. 25 and 26). Inthis case, the device can enhanced by driving it using a limited currentsource to prevent damage to the LED die. By combining this constructionwith other constructions such as those using multiple emitting LED diewith RGB, RGBY, BY and B(phosphor) patterns, a source lighting devicecan be provided that is variable in both color and intensity.

FIG. 81 is a photograph showing a higher voltage device cut from thedevice shown in FIG. 80 and constructed to be driven at 12 volts DC whenconnected in either polarity (top device) compared with a conventionallyconstructed printed circuit board having conventionally packaged LEDlamp, resistors, and rectifying diodes soldered to a conventional PCB(bottom device). FIG. 82 is a photograph showing a notebook computerkeyboard light constructed along the lines of FIGS. 18 to 20. FIG. 83 isa photograph showing the notebook computer keyboard light shown in FIG.82 lighting up a notebook computer keyboard. FIG. 84 shows a thin,lightweight, flexible pixilated scrolling message display constructedalong the lines of FIG. 3. FIG. 85 is a photograph showing a largeformat, thin, lightweight, flexible display having assembled displaytiles making up individual display pixels. FIG. 86 is a photograph of acoin battery light sheet constructed along the lines shown in FIGS. 71through 75 before being formed and showing the forming die. FIG. 87 is aphotograph of the coin battery light sheet shown in FIG. 86 after beingformed and with a coin battery inserted. FIG. 88 shows a light sheetbeing used to light up a cup holder. FIG. 89 shows a light sheet havingmultiple light sheet strips constructed along the lines shown in FIGS.51-53 for being used as a fishing lure. FIG. 90 shows a thin, flexiblelight sheet constructed on a half-hard copper back substrate and havinga size of about 8 inches square. FIG. 91 shows an infra-red light sheetfor providing identification through the emission of a wavelength thatis invisible to human vision.

The various elements making up each embodiment of the inventive devicesand the various steps performed in the inventive methods can beinterchanged in a variety of iterations, not all of which are providedas specific embodiments or examples herein. For example,function-enhancing components, such as phosphors, described in oneembodiment may be employed, although not specifically described, in analternative construction of another embodiment. Such iterations arespecifically included within the scope of the inventions describedherein.

With respect to the above description, it is realized that the optimumdimensional relationships for parts of the invention, includingvariations in size, materials, shape, form, function, and manner ofoperation, assembly and use, are deemed readily apparent and obvious toone skilled in the art. All equivalent relationships to thoseillustrated in the drawings and described in the specification areintended to be encompassed by the present invention.

Therefore, the foregoing is considered as illustrative only of theprinciples of the invention. Further, since numerous modifications andchanges will readily occur to those skilled in the art, it is notdesired to limit the invention to the exact construction and operationshown and described. Accordingly, all suitable modifications andequivalents may be resorted to, falling within the scope of theinvention.

What is claimed is:
 1. A bare die semiconductor circuit, comprising: afirst substrate having an electrically conductive surface; a secondsubstrate having an electrically conductive surface; a first bare diesemiconductor circuit element having a first conductor and a secondconductor, the second conductor of the first bare die semiconductorcircuit element in electrical communication with the electricallyconductive surface of the first substrate; a second bare diesemiconductor circuit element having a first conductor and a secondconductor, the second conductor of the second bare die semiconductorcircuit element in electrical communication with the electricallyconductive surface of the second substrate; and a series connectingsubstrate having a conductive surface, said conductive surface of theseries connecting substrate in electrical communication with both thefirst conductor of the first bare die semiconductor circuit element andthe first conductor of the second bare die semiconductor circuitelement, the electrically conductive surface of the series connectingsubstrate being effective for putting the first bare die semiconductorcircuit element and the second bare die semiconductor circuit elementinto a series electrical connection.
 2. A bare die semiconductor circuitaccording to claim 1 wherein the electrically conductive surface of atleast the first substrate, the second substrate and the seriesconnecting substrate has a predetermined resistance value effective tocreate a ballast resistor in series with the first bare diesemiconductor circuit element and the second bare semiconductor circuitelement.
 3. A bare die semiconductor circuit according to claim 1further comprising: at least one subsequent bottom substrate havingsubsequent electrically conductive surface; subsequent bare diesemiconductor circuit elements in electrical communication with saidsubsequent electrically conductive surface; and at least one subsequenttop substrate having a subsequent top conductive surface in electricalcommunication with the subsequent bare die semiconductor circuitelements so that the subsequent bare die semiconductor circuit elementsare connected in series with the first bare die semiconductor circuitelement and the second bare die semiconductor circuit element.
 4. A baredie semiconductor circuit according to claim 1 further comprisingopposite polarity bare die semiconductor circuit elements electricallyconnected in respective opposite polarity to and along with the firstbare die semiconductor circuit element and the second bare diesemiconductor circuit element to form an electronic circuit thatconducts in both polarity directions.
 5. A bare die semiconductorcircuit according to claim 1 further comprising an adhesive adhering theseries connecting substrate to the first substrate and to the secondsubstrate, the adhesive adhering the first bare die semiconductorcircuit element to the first substrate and to the series connectingsubstrate while maintaining the electrical communication between thesecond conductor of the first bare die semiconductor circuit element tothe conductive surface of the first substrate and maintaining theelectrical communication between the first conductor of the first baredie semiconductor circuit element to the conductive surface of theseries connecting substrate, the adhesive adhering the second bare diesemiconductor circuit element to the second substrate and to the seriesconnecting substrate while maintaining the electrical communicationbetween the second conductor of the second bare die semiconductorcircuit element to the conductive surface of the second substrate andmaintaining the electrical communication between the first conductor ofthe second bare die semiconductor circuit element to the conductivesurface of the series connecting substrate.
 6. A light emitting deviceaccording to claim 5 wherein the adhesive comprises at least one of athermally active adhesive, a catalyst active adhesive, a solventevaporation active adhesive and a radiation active adhesive.
 7. A lightemitting device according to claim 5 wherein the first and the secondbare die semiconductor circuit elements are at least partially embeddedin the adhesive with a respective top conductive side and bottomconductive side left at least partially uncovered by the adhesive sothat the adhesive binds the first substrate and the second substrate tothe series connecting substrate with the first and the second bare diesemiconductor circuit elements in electrical communication with therespective conductive surfaces.
 8. A bare die semiconductor circuit,comprising: a first substrate having an electrically conductive surface;a second substrate having an electrically conductive surface; a firstbare die semiconductor circuit element having a first conductor and asecond conductor, the second conductor of the first bare diesemiconductor circuit element in electrical communication with theelectrically conductive surface of the first substrate; a second baredie semiconductor circuit element having a first conductor and a secondconductor, the second conductor of the second bare die semiconductorcircuit element in electrical communication with the electricallyconductive surface of the second substrate; a series connectingsubstrate having a conductive surface, said conductive surface of theseries connecting substrate in electrical communication with both thefirst conductor of the first bare die semiconductor circuit element andthe first conductor of the second bare die semiconductor circuitelement, the electrically conductive surface of the series connectingsubstrate being effective for putting the first bare die semiconductorcircuit element and the second bare die semiconductor circuit elementinto a series electrical connection; at least one subsequent bottomsubstrate having subsequent electrically conductive surface; subsequentbare die semiconductor circuit elements in electrical communication withsaid subsequent electrically conductive surface; and at least onesubsequent top substrate having a subsequent top conductive surface inelectrical communication with the subsequent bare die semiconductorcircuit elements so that the subsequent bare die semiconductor circuitelements are connected in series with the first bare die semiconductorcircuit element and the second bare die semiconductor circuit element.